1. Field of the Invention
The present invention relates to an antistatic agent and an antistatic resin composition and an antistatic resin formed product.
2. Description of the Related Art
Plastics have excellent properties such as easy processability, high productivity, light weight and relative low procuring cost, so they are used for the parts and structural materials for automobile, autobicycle, scooter, television, radio, audio equipment, washing machine, rice cooker, personal computer, portable telephone, game machinery, building materials, office supplies, stationery, toys, sports goods, sports equipment, agricultural tools, marine tools, sheet and film.
They are usually prepared by plastic processing methods such as injection molding, blow molding, compression molding, transfer molding, rotating molding, slush molding, inflation tubular film process, and extrusion molding.
Plastic resins, especially polyethylene or polypropylene which have no polar group in the molecule are strong electrical insulating resistant, resulting in the easy generation of static electricity when similar or different plastic resins are rubbed, consequently they take an electrical charge.
When formed, the plastic resin products take an electrical charge, so that they adsorb the dust in surrounding, resulting not only to make their appearance worse but also to give uncomfortable feeling when workers or users touch them.
Electrical charging sometimes becomes the cause of ignition and occasionally generates troubles of production stoppage owing to the plastic resin formed product's surrounding and to the processing machine at the production step.
Also, electrical charging of the plastic resin formed product gives a bad influence when they are printed, painted or corona discharged.
As a preventing means for electrical discharging, there has been practiced methods such as coating a surface active agent on the surface of the plastic mold or plastic film; mixing a surface active agent by kneading into plastics; immersing the plastic product into a surface active agent solution; or spraying a surface active agent on the plastic product.
There are many kinds of surface active agents such as anionic, nonionic, cationic and amphoionic type.
Anionic type surface active agents are inferior at compatibility with plastics and make the plastics product's transparency worse. Nonionic type surface active agents have better compatibility with plastic than anionic type surface active agents, however nonionic types gradually lose their antistatic effect with the passing of time and nonionic types bleed out from inside of the plastic to the surface of it to cause whitening of the surface, resulting worse the product appearance.
Cationic and amphoionic type surface active agents are inferior at heat resistance causing coloring notwithstanding their good antistatic effect.
The above mentioned problems of each surface active agent are expected to improve. An antistatic agent containing an organic boron compound is disclosed in the Japanese Laid-open Patent 4-252287, the organic boron compound which is obtained by reacting an alcohol residual group containg compound having two adjacent hydroxyl groups with boric acid or borate ester.
The organic boron compound overcomes short durable terms of antistatic effect and whitening of the surface of plastic molded product by bleeding of the organic boron compound.